Se ha producido un error inesperado.
java.lang.NullPointerException
	at com.cranconsulting.pandora.Collection.sort(Collection.scala:312)
	at com.cranconsulting.pandora.PandoraTool$$anonfun$select$1.apply(PandoraTool.scala:387)
	at com.cranconsulting.pandora.PandoraTool$$anonfun$select$1.apply(PandoraTool.scala:380)
	at com.cranconsulting.pandora.ToolResult$.withToolResult(ToolResult.scala:23)
	at com.cranconsulting.pandora.PandoraTool.select(PandoraTool.scala:379)
	at sun.reflect.GeneratedMethodAccessor74.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:567)
	at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:71)
	at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:142)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311)
	at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342)
	at org.apache.velocity.Template.merge(Template.java:356)
	at org.apache.velocity.Template.merge(Template.java:260)
	at org.apache.velocity.tools.view.VelocityView.performMerge(VelocityView.java:942)
	at org.apache.velocity.tools.view.VelocityView.merge(VelocityView.java:902)
	at com.cranconsulting.pandora.PandoraServlet.mergeTemplate(PandoraServlet.scala:60)
	at org.apache.velocity.tools.view.VelocityViewServlet.doRequest(VelocityViewServlet.java:220)
	at org.apache.velocity.tools.view.VelocityViewServlet.doGet(VelocityViewServlet.java:182)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:547)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1359)
	at org.eclipse.jetty.servlets.UserAgentFilter.doFilter(UserAgentFilter.java:77)
	at org.eclipse.jetty.servlets.GzipFilter.doFilter(GzipFilter.java:181)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1330)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:478)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:483)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:941)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:409)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:875)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:250)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)
	at org.eclipse.jetty.server.Server.handle(Server.java:345)
	at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:441)
	at org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:919)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:582)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:218)
	at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:51)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:586)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:44)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:598)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:533)
	at java.lang.Thread.run(Unknown Source)